Equinox 20th March 2021 - simple sundial with only the (straight) equinoctial line @TheOwlman

Owlman At an equinox, the path of the shadow from the tip of a sundial's gnomon traces a straight line, regardless of the latitude of the sundial.

This video is a timelapse of a simple sundial that only has an equinoctial line and shows this straight line path.

For those who didn't come here from Zach Star's video: I sweepingly assert "at any latitude" - this is not strictly true, rather it is practically true for anyone likely to view this video. For the absolute mathematical truth please go and watch Zach's video youtube.com/watch?v=TfoTBKSIzlM

I became fed up with being told by flat Earthers that sundials would work exactly the same on their pancake world, though they could never supply the equations that would allow me to plot the straight line used in this video. I know, shocker.

updated 5 years ago

Equinox 20th March 2021 - simple sundial with only the (straight) equinoctial line

Owlman 2021-03-29 | At an equinox, the path of the shadow from the tip of a sundial's gnomon traces a straight line, regardless of the latitude of the sundial.

This video is a timelapse of a simple sundial that only has an equinoctial line and shows this straight line path.

For those who didn't come here from Zach Star's video: I sweepingly assert "at any latitude" - this is not strictly true, rather it is practically true for anyone likely to view this video. For the absolute mathematical truth please go and watch Zach's video youtube.com/watch?v=TfoTBKSIzlM

I became fed up with being told by flat Earthers that sundials would work exactly the same on their pancake world, though they could never supply the equations that would allow me to plot the straight line used in this video. I know, shocker.

Equinox sundial - raw footage

Owlman 2021-03-29 | Don't buy a cheap tripod, otherwise you have alot of work to do to make a timelapse video.